Traffic lanes are delineated by using pavement markings, retroreflective markers, point source lamps, and recently, lighted guidance tubes. Painted pavement markings are often difficult for drivers to see at night, so retroreflective markers have been developed to improve the ability of the drivers to locate and see the markers. While retroreflective markers retroreflect incident light, they do not provide any illumination. For some applications, such as marking railroad crossings or construction work zones, illumination is desirable, possibly used in conjunction with retroreflective markings, to increase the ability of drivers to see the marked area. For example, gate arms, particularly at railroad crossings, are marked with diagonal stripes, typically alternating red and white. The stripes are painted or are retroreflective sheeting. Red steady burn or flashing lights often accompany the gate arms. Construction barricades also typically are marked with diagonal stripes. Red or orange lights are often mounted on top of the barricades. The lights mounted on top typically have a life of ten to twenty days, depending on the time of year, and for flashing lights, two to three months. The lights usually run on two six-volt lantern batteries.
Illumination, in the form of lighted guidance tubes, has also been used to mark roadways. Lighted guidance tubes utilize a thin, flexible film made of a transparent polymeric material having a structured surface and a smooth surface, wherein light striking either surface is totally internally reflected. An example of this type of film is described in commonly-assigned U.S. Pat. No. 4,906,070 to Cobb, Jr. An example of a lighted guidance tube is described in commonly-assigned U.S. Pat. No. 4,805,984 to Cobb, Jr. For lighted guidance tubes, a circular cross-sectional shape is used for superior light transport characteristics, to allow maximum distance between light sources. Because of the desire to illuminate as great a length as possible, highly collimated halogen light sources are usually used. These light sources, however, have low efficiency and a short life span. It is often preferable to use the lighted guidance tubes for poorly lit roadways, to ensure the driver can adequately follow the roadways. Often, however, it is difficult or uneconomical to provide electrical power for the light sources in the lighted guidance tubes in remote areas or where only a short delineation system is required.